The award announcement cited his commitment to and achievements in astronomy education, as well as his groundbreaking research in observational cosmology. After receiving the award, he delivered a plenary lecture, "Evidence from Type Ia Supernovae for an Accelerating Universe and Dark Energy."

In November 2006, Filippenko also received the national Professor of the Year Award for doctoral and research universities, which is sponsored by The Carnegie Foundation for the Advancement of Teaching and administered by the Council for Advancement and Support of Education (CASE). In 2004, he received the Carl Sagan Prize for Science Popularization.

Filippenko has won acclaim for his work using supernovae as cosmic mile markers to demonstrate not only that the universe is expanding, but also that this expansion is currently accelerating. This discovery by the High-z Supernova Search Team and by the Supernova Cosmology Project was named "Top Science Breakthrough of 1998" by Science magazine. Filippenko was a member of both teams when the research was conducted.

"I am deeply honored to receive the Richtmyer Award," Filippenko said. "It recognizes the importance of the discovery of dark energy and the accelerating expansion of the universe, as well as my extensive efforts to educate the general public about this unexpected result and other breakthroughs in astrophysics."

A recipient of UC Berkeley's two most coveted teaching awards - the Distinguished Teaching Award and the Donald Sterling Noyce Prize for Excellence in Undergraduate Teaching - Filippenko is also the co-author of the introductory astronomy textbook, "The Cosmos: Astronomy in the New Millennium," now in its third edition. He has also taped several video lecture courses on astronomy for the Teaching Company.

One of the world's most highly cited astronomers, Filippenko has coauthored about 500 publications. He has won numerous awards for his research, including the Pierce Prize of the American Astronomical Society, the Canadian Astronomical Society's Petrie Prize, and a Guggenheim Fellowship. Filippenko has been the primary advisor for about two dozen UC Berkeley graduate students and postdoctoral fellows, as well as for more than 60 undergraduate research students.

Filippenko received his B.A. in physics from UC Santa Barbara in 1979 and his Ph.D. in astronomy from Caltech in 1984. He then became a Miller Research Fellow at UC Berkeley, and he joined the UC Berkeley faculty in 1986.

Established in 1941, the Richtmyer Memorial Lecture is named for Floyd K. Richtmyer, a distinguished physicist, teacher and administrator who had a wide influence on the development of physics in the United States. Previous award winners include UC Berkeley Chancellor Robert J. Birgeneau (1989); Director Steven Chu of the Lawrence Berkeley National Laboratory (1990), who also is a UC Berkeley professor of physics and a physics Nobelist; and UC Berkeley physicists Charles Townes (1959), Carlos Bustamante (2005), Emilio Segre (1957) and J. Robert Oppenheimer (1947).

The $7,500 monetary award includes travel to the annual AAPT meeting in Seattle, which is being held in conjunction with the national meeting of the American Astronomical Society.